---
hide_title: true
title: 'FontSizeExtension'
---

import Basic from '../../website/extension-examples/extension-font-size/basic';

# `FontSizeExtension`

## Summary

Add a font size to the selected text (or text within a specified range).

## Usage

### Installation

This extension is installed for you when you install the main `remirror` package.

You can use the imports in the following way:

```ts
import { FontSizeExtension } from 'remirror/extensions';
```

The extension is provided by the `@remirror/extension-font-size` package.

### Examples

<Basic />

### JSON Content

Initial content can be provided as JSON instead of HTML. Here is how you would provide the size mark.

```tsx
import { FontSizeExtension } from 'remirror/extensions';
import { useRemirror } from '@remirror/react';

const { manager, state } = useRemirror({
  extensions: () => [new FontSizeExtension()],

  content: {
    type: 'doc',
    content: [
      {
        type: 'paragraph',
        content: [
          { type: 'text', text: 'Hello ', marks: [{ type: 'fontSize', attrs: { size: '20pt' } }] },
        ],
      },
    ],
  },
});
```

Make sure you include the size unit in the mark because it can throw an error without a unit.

## API

- [FontSizeExtension](../api/extension-font-size)
